江河水污垢对小管径恒壁温管内对流换热影响

为有效提高江河水冷热源的利用率，应用热力学第一、第二定律和湍流流动理论，讨论和分析了污垢对恒壁温小管径管内对流换热过程热力学性能的影响。分析结果表明，有污垢存在时，污垢层导热引起的熵产在管内对流传热熵产中占主要部分，而温差传热引起的熵产则相对较小，且在雷诺数较大，管径较小的流动中，会出现粘性流动引起的熵产大于温差传热引起的熵产；随雷诺数的增大和污垢热阻的产生，熵增率都是单调增加的。因此在利用江河水发展水源热泵时，要充分考虑污垢热阻对换热器性能的影响，尤其是污垢层导热热阻的影响。

Thermodynamic Analysis of River Water Fouling on Constant Wall Temperature Tube of Small Diameter

In order to improve utilization of cold and heat source from river, turbulence theory and entropy generation theory were adopted to analyze the effect of fouling on convective heat transfer performance in small diameter tube of constant wall temperature. It is found that the entropy generation caused by conduction of fouling plays a more important role in total entropy generation of heat transfer process through a duct than that in cveast rate of caused by temperature difference. The entropy generation caused by viscous flow is more than the entropy generation caused by temperature difference in flow with bigger Reynolds and small radius. The increase rate of entropy generation monotonically increase with Reynolds and the generation process of fouling resistance. Thereafter, the effect of fouling resistance on the heat transfer performance of water source heat pump heat exchanger should he paid more attention, when river water are used as the cold and heat source of heat pump.